It would be better if we had the original PDF - but it is large. 11813 x 26575 pix. so a question.
Do those marks show when the original PDF (Bassilour totem 0129) is displayed in a PDF viewer ?
Do you know if the PDF was created from smaller images (tiles) joined together ? The lines in your screenshot are at 6000 pix vertical and 16000 pix horizontal which might be edges.
The fix in Gimp is not difficult, paint them out using the clone tool or using plugins such as resynthesizer or gimp_gmic_qt
Do those marks show when the original PDF (Bassilour totem 0129) is displayed in a PDF viewer ?
Do you know if the PDF was created from smaller images (tiles) joined together ? The lines in your screenshot are at 6000 pix vertical and 16000 pix horizontal which might be edges.
The fix in Gimp is not difficult, paint them out using the clone tool or using plugins such as resynthesizer or gimp_gmic_qt